Abstract

Smooth voids are achieved in an anisotropic crystal with a high refractive index by use of a femtosecond laser-driven microexplosion method. Due to the anisotropy of the crystal, the maximum fabrication depth and the fabrication power threshold are different in different crystal directions, indicating that the direction perpendicular to the crystal axis is more suitable for thick three-dimensional structure fabrication. The dependence of the threshold power on the illumination wavelength shows that the microexplosion mechanism is caused by a two-photon absorption process. As a result, a near threshold fabrication method can be used to generate quasispherical voids.

Received 20 June 2005Accepted 14 October 2005Published online 06 December 2005

Acknowledgments:

The authors would like to thank Dr. James Wang for the measurement of AFM images. This work was produced with the assistance of the Australian Research Council under the ARC Centres of Excellence Program. CUDOS (the Centre for Ultrahigh-bandwidth Devices for Optical Systems) is an ARC Centre of Excellence.